Salvage logging after the 1939 wildfires in Victoria, Australia, contributed to a
shortage of cavity trees for more than 40 species of vertebrates, including highly
endangered ones like Leadbeater's possum.Courtesy Museum
Victoria.

Log it or leave it?
Along a line in the New Hampshire woods, two forestry philosophies meet head to head.
On one side, ferns and moss coat immense logs lying flat among the trees. Here, saplings
and shrubs mingle in a lush understory that ripples with the mounds and pits left behind by
trees uprooted six decades earlier. On the other side, 60-year-old trees overtop decaying
stumps on a comparatively bare forest floor. Both forests are products of the notorious New England hurricane of 1938.
A study in contrast: The photo on the left shows a portion of
Pisgah Forest four years after the 1938 New England Hurricane. The image
on the right shows a nearby forest in Petersham, Mass., during a
salvage logging operation just after the storm.Photo courtesy Harvard
Forest archives.

The difference results from a decision by managers of the Harvard-owned acreage in
Pisgah Forest to let the former old-growth forest repair itself in the wake of the storm.
Meanwhile, private landowners and government-funded foresters swept away downed and
damaged trees elsewhere, including the adjoining portion of Pisgah. In the end, "it was
part of the largest salvage operation in U.S. history. Something like 50 percent of the
landscape was subjected to salvage logging," says forest ecologist David Foster.

The scene, as described to The Why Files by Foster, represents a great debate: Should
damaged trees be harvested from forests after natural disasters? After a disturbance, it's
tempting to think of affected forests as "lost" or "destroyed" says Foster, who is Director of
the Harvard Forest near Cambridge,
Mass. "The large trees as standing, living, majestic individuals are lost, but they're
still part of the system."

The urge to purge
Salvage
logging has been routine for centuries, often in the name of conservation.

We can see the appeal. Collecting timber from fire-ravaged hills can offset economic loss
and satisfy people who like a clean landscape. And, some say, picking the ground clean of
litter helps prevent more fires. (Similar logic exists in recent plans to thin national forests in
the name of protecting them. Read about the administration's
"Healthy Forest Initiative" here. Critics have some objections.) In accordance
with that line of thinking, federal and state plans after floods, hurricanes and fires often invite
logging.

It happens on a local scale too. "This is often the attitude of a land owner, a land trust, a
town board, or a state agency," Foster notes. When people see a damaged forest, their
first sense is often that the value has dropped and the land has been scarred. What they
want, Foster says, is to recoup some of that loss.

But before we all howl "timber!" Foster has a warning: Stripping forests of trees, even
dead ones, blocks the best rebound around. When left intact, ecosystems will repair
themselves after extreme weather.

Responding to a "general U.S. administrative hubris regarding the human ability to
restore, improve, or repair nature better than nature," Foster and six colleagues called for
policies that protect forests in the wake of disturbances in a recent issue of the journal
Science.

The authors cite three incentives to leave the logs alone:

The human activities associated with going into disturbed areas can themselves be
damaging. Roads and
machinery disrupt wildlife and encourage erosion.

Many trees damaged in a disturbance don't die, at least not abruptly. In a windstorm, for
example, many trees that get knocked flat die very slowly or stay alive. "They are a very
important part of the recovery process," Foster says.

The push comes at a time of controversy over U.S. Forest Plans to harvest 29,000 acres
of timber in Oregon's Siskiyou National Forest, a region consumed by wildfires in 2002. Critics of the plan,
reportedly including the authors of a new EPA review, say logging the area would trigger erosion and watershed pollution.

The critics are probably right, Foster says, in light of history:

Salvage logging after the 1938 New England hurricane disturbed rivers and streams. It
also left the soil more vulnerable to occasional fires in the decades since. Soil in logged
areas loses more nutrients and suffers more erosion than soil in the regions left intact after
the storm.

In 1997 and 1998, after an El Niño-induced drought, Southeast Asia was ravaged by
wildfires. In Indonesia alone, more than ten million hectares (about 4,660 square miles) of
forest burned. The unbridled logging that followed has hindered, or entirely
prevented, forest regrowth.

Harvard's hurricane factory
Foster's own research supports the same thesis. He and a group of graduate students
once tackled a stand of trees in the Harvard Forest in the name of science, not commerce.
Using winches and other machinery, the group pulled the trees down -- uprooting some,
leaving others in the ground -- to mimic a hurricane's effects. In an adjacent spot, the
group performed a mock salvage harvest. The rest was left to self-medicate.

"It was quite a surprise," Foster reports more than a decade later. In the un-logged
plot,"the major processes you'd follow in a forest -- the way nutrients are cycled, or the
way water moves through the forest -- they were completely unchanged even though
there was this catastrophe.

"In point of fact, disturbances are natural, ecosystems have tremendous resilience and
great value -- human, environmental, educational -- comes from leaving disturbed areas
alone and allowing them to recover naturally."